Effective catering requires a lot of equipment, but fortunately a good bit of it can be rented. While you'll need your own vehicle and basics like food warming equipment, items like chocolate and beverage fountains, margarita machines, and the like can usually be found at a local rental company.
If you're thinking about hiring a catering company for your event, be sure to ask for referrals before you make your selection, and be sure to interview several companies before choosing one. Price is important, but don't let it override other factors like quality and experience.